Minimum number of marbles to have taken one of each colour.

Q9: In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 greenmarbles. How many will he have to take out of his pocket to ensurethat he has taken out at least one of each color?A. 11B. 7C. 8D. 9
how??

Q9: In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 greenmarbles. How many will he have to take out of his pocket to ensurethat he has taken out at least one of each color?A. 11B. 7C. 8D. 9
how??

Consider the case that he took out the blue and the green marbles first (= 8 marbles). Then the next one must be a red one and he then has gotten all three colours.